I have a reacting flow with a CHEMKIN mechanism imported in FLUENT. Files imported include a mechanism file, thermo file and transport prop file. And there are about 1% CH3CHO with 99% helium in it. There are about 20 rxns in this process.

Right now I am running the case in serial. The grid number is OK. Without rxn, the iteration is fast but with rxn, the iteration cost an amazingly long time. Can anybody helps a bit?